Embedded Systems

Today, we continued to talk about debouncing and some other ways we can use it. We also talked about embedded systems and how they use state machines. In the lab, we began to build libraries of functions so we can use it in the future to simplify complicated code.

• Can use multiple bits to represent different changes / events
  • E.g. first 2 bits RR, second 2 bits RL, third 2 bits FR, last 2 bits FL
• Event Driven Programming / Programming Embedded Systems
  • Asynchronous, simultaneous, Sequence of inputs are unknown, unknowable, and reorderable
  • Typically, the program never ends or exits
• State Machines
  • can be drawn through circles
  • At any point in time, the state machine can be in ONE and only ONE of a finite fixed number of "states"
  • technically, cannot be in between states, but computers are not instantaneous
  • progression in states depends ONLY on the current state & events
  • useful tool for describing the behavior of event driven systems
  • MOST IMPORTANTLY: allows you to explore design before you code
• Dining Philosophers Problem
  • a number of philosophers are sitting around a table, each with 1 fork
  • need 2 forks to eat the spaghetti in the center of the table
  • can be modeled with a state machine where table owns forks
  • Harel 1887

There two pieces of code do the exact same thing!

Despite that, this one, the second one, is much easier to read.